Field of the Invention
The present invention relates to a solar cell and a fabrication method thereof, and more particularly, to a fabrication method of a silicon solar cell, especially, a slim-type solar cell capable of providing a high efficiency at economical unit costs by improving process conditions suitable for a slim-type silicon substrate.
Description of the Related Art
Recently, due to problems such as a rapid rise in oil prices, an environmental problem of the earth, exhaustion of fossil energy, waste treatment in nuclear power generation, location selection according to construction of a new power plant, etc., interest in renewable energy has increased and among others, research and development for a solar cell, which is a pollution-free energy source, has actively proceeded.
A solar cell is advantageous in view of being pollution-free, being a sustainable resource, having a semi-permanent life span, etc., and being expected as a source of energy to allow human beings to ultimately solve the energy problem, without adversely affecting the environment.
Solar cells may be typed as a silicon solar cell, a thin film solar cell, a dye sensitized solar cell, and an organic polymer solar cell, etc., according to their constitutional material. In particular, a crystalline silicon solar cell makes up a majority of the total production of the solar cells in the world over. The crystalline silicon solar cell has a higher efficiency compared to that of other solar cells, and a technique to lower the unit cost of manufacturing crystalline silicon solar cell has continuously progressed, such that the crystalline silicon solar cell may be referred to as the most popular type of solar cell.
Solar cells are generally fabricated to include a p-n junction interface by forming an n-type semiconductor layer on a front surface of a p-type silicon substrate. The n-type semiconductor layer formed on the front surface of the p-type silicon substrate acts as an emitter, wherein an antireflection film of silicon nitride or silicon oxide is coated thereon, and then electrodes are wired in such a way to minimize reflection of light.
Recently, studies that allow the solar cells to have a high photovoltaic efficiency by improving a structure of the emitter in a portion where the front electrode of the solar cell is wired or by controlling a production process of the solar cells have been made.